Four Dead at Fort Hood, Three Victims Plus Gunman Killed

Krystina Cassidy and Dianna Simpson attempt to make contact with their husbands who are stationed inside Fort Hood, while standing outside of the Bernie Beck Gate, on April 2, 2014, in Fort Hood, Texas. Tamir Kalifa / AP

A U.S. military official told NBC News that Lopez was an active-duty soldier who was assigned to a Sustainment Brigade.

All of the wounded and killed were also military, according to Lt. General Mark Milley, who spoke to reporters at the base after the shooting.

Milley, who didn't use Lopez's name pending family notification, said that the gunman was being evaluated for post traumatic stress disorder, and had self reported a traumatic brain injury.

The soldier had not been wounded in Iraq, but was being treated for behavioral problems, anxiety and "a number of other psychological issues," according to Milley.

The soldier "put his hands up and then reached under his jacket" when a female officer drew her weapon, Milley said. "He pulled out the gun, and she engaged, and he put the weapon to his head."

“Experience has taught us many things here at Fort Hood. We know the community is strong .... The soldiers who have served so bravely through the last 13 years in Iraq are strong, and we will get through this.”

Milley said that the shootings didn't appear to be related to terrorism or radicalism but that nothing had been ruled out so early in the investigation.

The soldier's body was found in a parking lot near the First Medical Brigade area, Milley said. His weapon had been bought in the area recently and wasn't registered with the base.

Three other people died in local hospitals, Milley said.

Doctors at Scott & White Memorial Hospital said they were treating eight patients — seven men and one woman. Three of the patients were said to be in critical condition and on ventilators, while five others were in serious condition.

Maj. Nidal Hasan was convicted in August for killing 13 people in November 2009 and injuring 32 others. He has since been sentenced to death.

In September, a gunman opened fire at the Washington Navy Yard, killing 12 and wounding four before being slain by police. Last month, a civilian shot dead a sailor aboard a ship at a U.S. Navy base in Norfolk, Va.

Courtney Kube, Tom Winter, Tracy Connor, Hasani Gittens and Monica Alba of NBC News contributed to this report. This is a developing story. Refresh this page for more.